Red Zone

What does Red Zone Mean?

A term used for the space from the defending team's twenty-yard
line to the goal line. An offense is considered to have a high
probability of scoring when they enter the red zone, because they
are within field goal range for most kickers, and only have a short
distance to go in order to score a touchdown.

Sporting Charts explains Red Zone

The red zone is used to evaluate an offense's effectiveness at
converting possessions into points. Teams with a high red zone
efficiency will score touchdowns the majority of times they enter
the red zone. Typically, it is thought that the worst an offense
should accomplish once they enter the red zone would be a field
goal, since any field goal attempt in the red zone will be
thirty-seven yards or less and thus have a high probability of
success. The defense has one advantage in red zone in that the
offense has limited room to operate.